The invention relates generally to a compressor and more specifically to an apparatus and method for removing compressor blades.
A conventional gas turbine generally operates on the principle of compressing air within a compressor and then delivering the compressed air to a combustion chamber where fuel is added to the air and ignited. Afterwards, the resulting combustion mixture is delivered to the turbine section of the gas turbine where a portion of the energy, generated by the combustion process, is extracted by a turbine to drive the compressor via a shaft.
In multi-stage compressor sections, stators are placed at the entrance and exit of the compressor section, as well as between each compressor stage, for purposes of properly directing the airflow to each successive compressor stage. As a result, stators are able to enhance compressor performance by appropriately influencing airflow and pressure within the compressor section.
Stators generally consist of an annular array of airfoils or vanes. Stators are typically formed in segments as stator vane segments consisting of one or more airfoils supported by the base. The base includes a dovetail to maintain the stator vane unit within the casing. These stator vane segments are individually mounted to the compressor casing to form an annular array, so that the airfoils project radially between an adjacent pair of compressor stages. A rotor with blades occupies the space between the stator vanes. The rotor blades or airfoils are also connected to the rotor wheel via dovetail connection.
After prolonged use, the blades or airfoils of the compressor may need to be repaired or replaced. Some known methods for removing compressor blades from compressor wheels have relied on manual labor. In one method, a first person rests a V-shaped block mounted on the end of a long handle on the leading edge of a blade. A second person then swings a heavy sledgehammer and hits the back of the V-shaped block. This is repeated multiple times until the blade is removed from the wheel. This process is then repeated for the rest of the blades, and is a time consuming and may be a potentially hazardous activity. Another known method uses a hand-held pneumatic jack-hammer to bear on the blade until it is removed. This requires significant physical effort on the part of the jack-hammer operator and may also carry risk of injury.